Ventilated rain screen cladding systems are known in the prior art. Typically in a ventilated rain screen cladding system insulation is affixed exterior to the structural wall and a framework is attached exterior to the structural wall, often having brackets that traverse the exterior insulation. To the framework, cladding is attached, wherein the framework creates an air space between the exterior insulation and the cladding. The cladding is arranged such that the air space is ventilated to the outside air. Ventilated rain screen cladding systems partially dissipate heat from the sun because of the ventilated air space between the cladding and the exterior wall. The air space also serves to evacuate water and humidity that might have penetrated behind the cladding and serves to prevent condensation in the structural wall. Further, as the insulation is affixed exterior to the structural wall, the structural wall is protected from all but minor temperature variations.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. standard 90.1 is a standard that provides minimum requirements for energy efficient designs for buildings except for low-rise residential buildings. In order to attach a ventilated rain screen cladding systems to a building and be compliant with ASHRAE standard 90.1 regarding thermal breaks through the exterior foam insulation, only fasteners such as screws may traverse the exterior foam insulation.
Attachment systems of the prior art for ventilated rain screen systems where only fasteners traverse the exterior foam insulation are succeptible to compressing the exterior foam insulation, thereby reducing its insuating value. The exterior foam insulation employed is typically of an isocyanurate, styrofoam or similar type; typically, compressive force of 25 psi or greater is sought to be avoided so that crushing of these types of exterior foam insulations is reduced. In some of these prior art attachment systems, vertical load placed upon brackets attached by fasteners through the exterior foam insulation allows the brackets to be deflected downward causing the lower end of the bracket to make additional compressions at the lower end of the brackets. In other prior art attachment systems, the compression problems associated with the downward deflection of brackets is reduced by attaching long vertical members, typically of a c-channel configuration, with fasteners through the exterior foam insulation, to which brackets are then attached; This results in increased material costs and increased installation diffuculty.
Accordingly, objectives of the present invention are to provide a metal attachment system for ventilated rain screen cladding systems, that exceeds ASHRAE standard 90.1 regarding thermal breaks through exterior foam insulation, that prevents exterior foam insulation crushing, that is constructed on site of components of manageable size and minimal weight, that is of reduced cost, that is not sucseptible to insulation crushing through overtightening of fasteners, and that may also be utilized with lower density exterior insulation, such as mineral wool.